Feature: Add counts to radical/kanji/vocab sections

[Deadpikle]

Added counts for radicals, kanji, and vocab on various screens so you can see how many items remain or are in the given section. This info is displayed on the WaniKani website when browsing things by level, and I think it would be useful in the app.

Added to the following screens:

• Lesson picker
• Number of items remaining in level
• Number of items in whole level
• Apprentice/guru/etc. lists

Before

After